Ein einfacher Syntheseweg zu Lösungsmittel‐ stabilisierten Metallnanopartikeln und ihre Anwendung in der Hydrierung

By using a dedicated solvent and an appropriate metal precursor species, it is possible to build stable nanoparticle solutions in a fast and effective way. These solutions can be simply used in chemical reactions directly as a catalyst solution. With different transition metal species and solvents of variable polarity and density, a great number of catalytic reactions can be carried out. The catalyst can easily be recycled and, depending on the selection of the catalytic system, the solutions were stable over months.     

Waschverfahren partikulär‐disperser Systeme – Verfahrensspektrum und Aspekte der Verfahrensauswahl

Washing of Disperse Solid Systems – Existing Washing Processes and Guidelines for Choosing the Appropriate Washing Procedure Washing of disperse solid systems is a widely used and complex operation. Since the washing‐step is mostly integrated into other process operations, it is subject to numerous demands, which exceed the primary demands like a good separation result and a low specific wash liquid demand. Because of the phenomenology and limits of different washing procedures it is difficult to choose an appropriate washing process. Additionally, the acting transport mechanisms of some washing procedures are not yet sufficiently understood. This work shows a broad overview over the existing washing processes, the numerous parameters and the demands they have to fulfill. A categorization of washing procedures as well as a classification of the processes concerning their macroscopic transport phenomena are the base for a broad decision chart which compares and evaluates existing washing processes and shows their individual limits. The work can be seen as a rough guideline for choosing the appropriate washing procedure.     

Inline‐Bestimmung der CO2‐Beladung von wässrigem Diglykolamin in Abhängigkeit von Viskosität und Temperatur

The solvents CO₂ loading is an important factor when evaluating the efficiency of an absorption/desorption process. There is almost no possibility to measure the CO₂ loading inline. Therefore experiments were made to determine a correlation between the CO₂ loading and the solvents viscosity as well as the solvents temperature. The correlation was verified using control tests and values from the literature. An overall maximum relative error under 10 % could be observed. Simultaneously investigations were made to understand if the solvents electrical conductivity and pH value are suitable for a similar correlation.     

Numerische Simulation disperser Gas/Flüssig‐Strömungen in Blasensäulen bei hohen Gasgehalten mit OpenFOAM® Teil 1 – Grundlagen der Modellierung

Various chemical products are synthesized in processes using gas/liquid reactors with bubbly flows. Hence, there is significant interest in a more efficient process design as well as in process intensification with a strong focus on this reactor class. However, the design of industrial gas/liquid reactors requires more detailed information about the flow structures and characteristics of two‐ or multiphase systems. The basic models for two‐fluid model simulations of dispersed gas/liquid flows in bubble columns at high gas fractions are presented..     

Numerische Simulation disperser Gas/Flüssig‐Strömungen in Blasensäulen bei hohen Gasgehalten mit OpenFOAM®. Teil 2 – Numerische Simulation und Ergebnisse

The design of industrial gas/liquid reactors such as bubble columns requires detailed information with respect to the flow structure and characteristics of two‐ or multiphase systems in the reactor. The contribution is focused on the evaluation of the simulation results obtained by a selection of models. The results are further compared with those reported in literature. The simulations have been performed with the CFD software OpenFOAM®. The main focus of the numerical simulation was set on capturing the characteristic process and design parameters of bubble columns.     

Hydrodynamik und Stofftransport in einem Perlschnurreaktor für Gas/Flüssig/Fest‐Reaktionen

In this work, a pellet string reactor was characterized with respect to hydrodynamics and mass transfer. The catalyst packing consists of a cylindrical channel with a diameter of 1.41 mm, which was filled with spherical catalyst particles, having an outer diameter of 0.8 mm. Under reaction conditions (liquid phase hydrogenation of α‐methylstyrene) overall (gas‐liquid‐solid) volumetric mass transfer coefficients for hydrogen between 0.8 and 5.5 s^–1 were computed. Due to high mass transfer rates and simple reactor geometry, pellet string reactors can be applied in industry as highly efficient reaction units.